After perfunctorily checking the white folds of his robe for flecks of red, the executioner wipes his blade with a tissue, which he drops onto the corpse and walks away.

A sudden surge in public executions in Saudi Arabia in the last two months has coincided with a U.S.-led bombing campaign against Islamic State. This has led to inevitable comparisons in Western media between Islamic State's beheadings and those practiced in Saudi Arabia.

Defenders of the Saudi death penalty say beheadings, usually with a single sword stroke, are at least as humane as lethal injections in the United States. They deplore any comparison between the kingdom's execution of convicted criminals and Islamic State's extra-judicial killing of innocent hostages.

But rights activists say they are more concerned by the justice system behind the death penalty in the kingdom than by its particular method of execution. And critics of the Al Saud ruling family say the latest wave of executions may have a political message, with Riyadh determined to demonstrate its toughness at a moment of regional turmoil.